This invention relates to athletic shoe soles. It is a sole design to reduce leg muscle fatigue that results from athletic activity. Hereto, conventional atheletic shoes were primarily designed to provide an adequate shock absorbent cushion for feet and ankle protection, but these conventional soles lack a resilient platform that returns significant energy to the base of the foot. The inventive sole is an improvement in this field of invention because it performs the dual function of shock absorber and source of energy.
The inventive sole structure was filed as the "Verti-Flex Midsole" under the Disclosure Document Program on Mar. 19, 1986, Disclosure Document No. 146,411.
Other sole structures have been disclosed for both athletic and dress shoes in the patent literature. For example, U.S. Pat. No. 2,437,227 discloses the use of coil springs within a cushioning midsole layer and U.S. Pat. No. 4,535,553 discloses a shock absorbing sole layer of a plurality of transversely and longitudinally spaced discrete shockings projections.